This invention relates to a technique related to a substrate for bioassay. More particularly, the invention relates to a substrate and device suited for bioassay for measuring and detecting interaction between substances and also to a method for making the substrate.
At present, substrates that are called a DNA chip or DNA microarray (hereinafter referred generically to DNA chip) wherein a given DNA is (in full length or partly) microsequenced have been utilized for mutation evolution, SNP's (single nucleotide polymorphisms) analysis, a frequency analysis of genomic expression and the like and are now being used widely in other fields of drug discovery, clinical diagnosis, pharmacogenomics, forensic medicine and the like.
In the DNA chip, it is general to fix a nucleic acid strand called probe against a surface site of a reaction field provided on a substrate and detect hybridization between the probe nucleic acid strand waiting for at the reaction field and a fluorescence-labeled target nucleic acid strand by measuring an intensity of target nucleic acid-derived fluorescence.
Alternatively, a method of detecting hybridization has been proposed, in which an intercalator capable of emitting fluorescence through specific binding to a complementary strand produced by hybridization is used for measuring an intensity of fluorescence from the intercalator.
Still alternatively, there has also been proposed a technique wherein a counter electrode is provided at a reaction field on a DNA chip and an electric field is applied thereto, with which it is intended to improve a hybridization efficiency and detection accuracy by the electrodynamic action (see Japanese Laid-open Patent Application No. 2004-135512 as Patent Document 1).
In recent years, there have been proposed DNA chips, to which an information reading technique of optical disks such as CD, DVD and the like or an optical disk mastering technique is applied. For instance, Patent Document 2 (Japanese Laid-open Patent Application No. 2005-3450) discloses a DNA chip wherein a reaction region (corresponding to a data region) serving as a field of hybridization and address pits for obtaining positional information of the reaction region and rotational synchronism information on the same plane of a disk-shaped substrate (see FIG. 1 of Patent Document 2).
Patent Document 3 (Japanese Laid-open Patent Application No. 2004-93548) proposes a disk-shaped medium wherein microcapillaries capable of isolating a sample component by electrophoresis are formed.